An Radio Frequency IDentification (hereafter, referred to as “RFID”) system is a kind of a radio communication system which consists of RFID, an antenna, a reader and a writer, wherein the RFID is moved by attaching to an article and moves, and performs a radio communication with an antenna fixed on the ground or a building. The reader controls communication between an antenna and RFID or performs a protocol exchange between an upper-level device, such as a computer, and RFID. Recently, there are many readers with a built-in antenna.
RFID is one of the constituents of an RFID system. The RFID is required to satisfy the following three conditions concurrently: (i) the size should be convenient for carrying; (ii) information should be stored in an electronic circuit; and (iii) the communication should be made by non-contact communication. Accordingly, although a floppy disc, a magnetic card, a contact IC card, etc. are convenient to store data and to be carried, they are not included in RFID. Although RFID broadly covers a non-contact IC card (RF card), it generally refers to an RF tag.
RFID is used to identify an article, to which an RFID tag is attached, and information on the article. In other words, when and where a product exists, required information can be taken out and new information can be wrote down, if necessary. When using RFID, we can save time spending in inquiring an information center of required information and receiving the response. Further, this RFID system has advantages, such as an easy distributed process of information and simplification of information system.
In particular, an automatic identification means used in an automatic processing line should resist harsh environments, such as vibration and impact, water and oil, high temperature and dust, etc., under which RFID is suitable. Additionally, RFID is more suitable for the cases where batch production is made on one production line, and a frequent exchange of information on a target object is required. Although RFID was used as a substitution for a bar code at a relatively early logistics stage, such as a production process or a logistics center, it tends to be gradually extended to a final distribution stage, such a distribution stage.
The RFID tag refers to RFID attachable to an article, and is valuable in the field of an FA (Factory Automation). An RFID tag largely consists of a chip and an antenna, and has a completed shape through an encapsulation process to protect the RFID tag. The RFID tag has various shapes, such as a credit card, a stick, a coin, a label, etc., depending on an encapsulation method so that a user can select a shape suitable for his/her purpose. The RFID tag is independently separated and manufactured in the shape of piece. Hereinafter, an RFID tag previously manufactured in the shape of piece is referred to as an “independent RFID tag.”
However, where a plurality of RFID tags are required to form an RFID system (e.g., a location management system), the following problems are found in the previous independent RFID tag.
First, each of independent RFID tags has the same appearance and thus is not distinguishable from one another.
Second, even where RFID tags constituting the RFID system are installed at fixed intervals, they should be individually installed one by one, which is very cumbersome.
Third, in order to confirm ID of each independent RFID tag in the process of installing independent RFID tags, a user should read the tags one by one. Further, even if ID is wrote down on the surface of each independent RFID tag in or after the process of encapsulation of RFID, it is difficult to keep the order of these tags in the process of installation because these independent RFID tags are separated from one another one by one. Further, once the order has been scattered, management is more difficult.
Fourth, the more the plurality of independent RFID tags to be installed increases, the more seriousness of these problems increases.
Therefore, considerable time and workforce are required in order to install independent RFID tags, and at the same time unnecessary confusion is generated.